Catalytic oxidation of anthracene



Patented Nov. 1, I932 reg ALPHONS 0. JAEGER, OF GRAFTON, PENNSYLVANIA,ASSIGNOB, BY MESNE ASSIGN- MENTS, TO THE SELDEN RESEARCHKa ENGINEERINGCORPORATION, OF PITTSBURGH,

PENNSYLVANIA, A CORPORATION OF DELAWARE CATALYTIC OXIDATION OFANTHBACENE in Drawing. Original application filed June a, 1927, SerialNo. 196,393, now Patent No. 1,709,583, dated April 23, 1929. Divided andthis application filed March 24, 1928. Serial No. 264,571.

This invention relates to the, catalytic oxidation of anthracenetoanthraquinone in the vapor phase.

It has been proposed 1n the past to oxldize anthracene in the vaporphase admixed Wltll air or other oxygen-containing gases by pass ing.the mixture over contact masses containing metal elements of the fifthand sixth groups of the periodic system. The reaction is stronglyexothermic and tends to get outof control resulting in over oxidation,in some cases reaching total combustion with serious consideredto be inan unstable equilibrium,

and presents a very serious cooling problem. For this reason thecatalytlc vapor phase A 7 oxidation of anthracene to anthraquinone hasmetwith little practical commercial success. Not only does the largeevolution of heat which takes place When the reactionproceeds too farresult in serious losses in yield or contamination of the product butthe catalyst itself is frequently damaged by excessive temperatureswhich may cause surface sintering. 7

According to the present invention, catalysts or contact massescontaining catalytic elements, Whether diluted With carrier particles orundiluted, are associated With stabiliters, Which prevent to a largeextent undesired side reactions and permit a catalytic control whichallows excellent yields and higi outputs. The stabilizers used in thepresent invention are not to be considered as themselves catalysts. Infact, they are characterized by the fact that they contain basic radicals which in their basicity, Valence or stability of their oxides at hightemperatures toward oxidizing agents are radically different from thecharacteristics of the catalytic elements. The stabilizing elementswhich are usually present in the form of salts 'or other compounds arethe alkali metals, earth metals, some earth metals and other metalsWhich form oxides whichare not reducible my hydrogen, all of whichelements Will be referred to in the present invention asstabilizer'forming metals. The salts or other compounds of thesestabilizing elements produce a very desirable stabilizing effect, andpractically any of the salts can be used Which do not contain acidradicals having a deleterious efiect upon the particular reaction inwhich the catalyst is to be utilized. Thus, for example, the acid orneutral sulfates, phosphates, halides, chlorates, nitrates, cyanides,both simple and complex, arsenates, antimonates, bismuthates, borates,carbonates and the like give excellent results. 7 l

The stabilizers can be added to the catalysts or contact massescontaining the catalysts in a chemically preformed state, or they mayence of the other components of the contact mass. Thus, for example, astabilized vanadium pentoxide catalyst may be produced by addingpotassium bisulfate in suitable ing sulfur trioxide or sulfur dioxideand air,

or With dilute sulfuric acid, producing the vanadium oxide andpotasslumbisulfate in situ. In both cases, the potassium bisulfate willact as a stabilizer, but the action will not be the same as the physicalarrangement of the molecules, and perhaps to a certain-- extent thechemical combination is different With diiferent methods of producing acon tact mass having the same empirical chemical composition, and thecatalytic activity depends not only on the empirical chemicalcomposition, but also on the physical, arrangement and on the method offormation of the contact mass. Stabilizers can, of course, also begenerated in situ' by reaction of various acid bodies With stabilizerforming metal compounds of components other than the catalyst componentof the contact masses.

The stabilizers can be introduced or formed in situ in any desiredmanner, and in the case of diluted catalysts may be incorporated intothe alkaline v be produced by chemical reaction in the 'pre I In thecatalytic oxidation of anthracene to.

anthraquinone the presence of free alkali is undesirable in most contactmasses andany free alkali present can be readily neutralized bytreatment with acid gases as described in my prior Patent No. 1,678,627dated July 24, 1928. This treatment transforms any alkali present intothe alkali forming metal salts which act as non-alkalinestabilizers. 9.0

Any other suitable method of incorporating compounds of the stabilizerforming met als with catalysts or in contact masses may be used and areincluded in the present invention.

Diluting catalysts with finely divided or highly porous diluents isfrequently desirable, and such diluted catalysts may be associated withstabilizers or stabilizers may be formed therein. It is not definitelyknown whether diluents of desirable physical structure have anyinfluence on the efi'ect of the stabilizers or not, since any efi'ect onthe stabilizer is probably masked by corresponding effects on thecatalyst. Thus, diluents of high porosity or capillarity greatlyincrease the effectiveness of almost any catalyst and naturally, ofcourse, increase the eiiiciency of any corre sponding stabilizedcatalyst, but whether this added effectiveness is to be attributedpartly to effects on the stabilizer or wholly to eitects on the catalystis difiicult or impossible to prove and the present invention is notlimited to any theories of action of diluents.

WVhile all of the alkali forming metals may be used as stabilizers, Ihave found that stabilizers containing potassium give better resultsthan do stabilizers containing sodium with many of the contact masseswhich can be stabilized by the present invention. It will be clear, ofcourse, that the best stabilizer should be chosen for each catalyst.

It is not definitely known just how the stabilizer acts. I am of theopinion, however, that in many, if not most, catalytic oxidations oforganic compounds the most important effect is to reduce its activity intotal combustion. In the case of some vanadium oxide catalysts, thecolor shows that when sufiicient stabilizers of suitable type are added,all of the vanadium is not continuously regenerated to vanadiumpentoxide, as the catalyst shows various colors of blue, green and grayand does not remain yellow as is the case with an unstabilized vanadiumoxide catalyst. Whether, however, this is the only effect of a but onthe contrary, greatly increases the 7 overallefliciency,.that is to say,the output of the desired intermediate oxidation products per unit ofcatalyst per unit of time, and it may be that certain activitiesv otthecatalyst are actually enhanced and in fact this appears likely, becauseas has been stated above, all stabilizing elements are not equallyeffective in their reaction and it may well be that certain stabilizersactually enhance the.

catalytic power of the catalyst. While it is an advantage of the presentinvention that in 'many cases increased outputs are obtained withstabilized catalysts, the invention is in no sense limited to catalystsor processes in,

which the actual output is increased. In some cases, where extremepurity is desired, this can be obtained with a stabilized catalyst byreducing the loading and the advantages of the present invention can beenjoyed even though the'properties of the catalysts of the presentinvention are not utilized all in one direction, namely, increasing theoutput. As in all catalytic reactions there is a certaincompromisebetween'purity of product and output, and the best compromiseto be chosen in every case will be determined by'the skilled catalyticchemist.

l/Vhile it is advantageous in many cases to use an anthracene of highgrade, it is one of the great advantages of the present'invention' thatimpure anthracene, such as crude anthracenes which may contain varyingquantities of carbazole and phenanthrene as well as other impurities,may be oxidized to anthraquinone of good quality or to a product whichcontains a high percentage of anthraquinone readily separable from smallamounts of by-products. By the choice of suitablestabilized catalysts itis possible toselectively burn out one or more of the components of thecrude or impure anthracene. This is particularly true of carbazol, whichcan be almost quantitatively burned out without serious attack of theanthracene. Com- =posite catalysts may be used which favor the totalcombustion of impurities and the production of anthraqum'one or theprocess can be carried out in the presence of two different catalystspreferably arranged in zones,

one being a combustion catalyst forthe burni ing out of impurities andthe other being a specific anthraquinone catalyst. The use of suitablestabilizers makes this catalytic purification combined with oxidationreadily possible and is one of the most important features of thepresent invention, permitting as it does the use of anthracenes whichhad hitherto been considered worthless for catalytic oxidation toanthraquinone. lVhen the catalytic oxidation is carried out togetherwith or subsequent to catalytic combustion of impurities, it should beunderstood that stabilizers which are most effective for theanthraquinone oxidation catalysts are not necessarily the most effectivefor the burning out of impurities. Thus, for example, strongly alkalinestabilizers which are relaively less efficient for the oxidation ofanthracene are among the most efficient for the catalytic combustion ofcarbazole and similar impurities. In a combined process, therefore, itmay be necessary to use a compromise contact mass which containsstabilizers, which perhaps are not the most effective for anthraquinonebut which are fairly eifective for the production of anthraquinone andalso tend to favor the catalytic combustion of impurities. The bestcompromise will depend on the nature of the crude anthracene used andthe nature of the contact mass chosen. Of course where the process iscarried out in two stages, as for example when two different catalystsare arranged in zones, no problem is presented and the stabilizers bestsuited for each step can be present in the contact mass used for thatstep.

Stabilized catalysts when used in oxidation reactions according to thepresent invention bring about remarkably improve d results, and in manycases a stabilizer alone is sufficient. I have found, however, that theaddition of other chemical compounds'possessing cata- 'lytic activity,but not being specific catalysts for the particular reaction, appears toen harms the chest of the stabilizer and to tune it for more perfectresults for the individual reactions. as stabilizer promoters withoutthereby limiting the invention to any particular theory of action as itmay be that the stabilizer promoters do not act directly on thestabilizer itself. Among the stabilizer promotersare the usual catalyticcompounds containing the usual catalytic elements and particularly heavymetals and some amphoteric metals,

such as aluminum, zinc, lead and the like.

In general, of course, any catalytic element which is not a specificcatalyst for the reaction in question may, when combined with astabilized catalyst for that reaction, act as a stabilizer promoter.Among the most effective stabilizer promoters are, however, some of thecatalytic elements which are by themselves relatively mild catalysts andthe effect of the stabilizer promoter is not a pure additive one basedon the catalytic power of the elements present in the stabilizerpromoter; On the contrary, the results tend to indicate that there is adefinite cooperation between the'stabilizer promoter and the stabilizercatalysts These compounds will be referred to.

and in some cases, the addition of stabilizer promoters produces resultsgreatly in excess of those which would be predicted from the knowncatalytic power of the promoter ele-'- ments themselves. I

Stabilizer promoters may be added in a chemically preformed state orformed in situ as'has been described in the case of stabilizers, and theforms of introduction may take place in any suitable manner, as will beapparent to the skilled chemist. It is,however, by no means necessarythat the stabilizer promoters should be present as separatechemicalcompounds and on the contrary, many very effective catalysts may beproduced by the addition of compounds of the stabilizing forming metalswith various stabilizer promoter elements. Thus, for exa1nple,thevarious alkali metal metallates form excellent composite stabilizers andstabilizer promoters. It is possible, of course, that during reactionthese com- )ounds break u )to a certain extent and erhaps even insuchcases'the stabilizer becomes completely dissociated from the stabilizerpromoter. It is impossible, however, to determine ust whattakes placewithin the catalyst during catalysis, and I do not wish to limit myinvention to any theory.

In addition to stabilizers and stabilizer promoters, which are presentor are intro duced as individual chemical compounds or combinedchemically with each other, the stabilizer promoters may be present inchemical combination with various diluents.

Thus, for example, many heavy or other metal 7 silicates form at thesame time excellent dilucuts and stabilizer promoters. Notable examplesof these compounds are various zeolites in which heavy metal or otherelementsare present in exchangeable or non-exchangeable form. Thesezeolites, and, in fact, base ex changing bodies generally, whetherzeolites or non silicious base exchange bodies, possess for the mostpart a microporous structure which isexcellently suited as a catalystdilu- 3 cut or as a framework in or onwhich catalytically activeelements may be hung. Such base exchange bodies permit in some casesalso a chemical combination between the stabilizer, stabilizer promoterand the catalyst itself. Thus, forexample, a zeolite or other baseexchange body may contain a catalytically acapplication of myself andJohann A. Bertsch,

Serial No. 95,771, filed March 18, 1926 and Patent No. 1,701,075 datedFebruary 5,1929,

iii

-mixed and treated with 25 parts of freshly parts of enhance theeffectiveness of the contact mass.

used. The action of the diluents, particularly the porous diluentsappears to be primarily due to their physical characteristics.Catalytically active components which are not catalysts for theparticular reaction are classified under stabilizer promoters, although,of course, it is difficult in some extreme cases to draw a line betweendiluents and stabilizer promoters in the case of certain compounds whichappear to have weak catalytic activity which may be due to theirphysical or to their chemical characteristics. In general, however,where components which do not possess fairly high catalytic activity, asa result of their chemical structure, they are to be classed as diluentsrather than stabilizer promoters.

The invention will be described in greater detail in connection with thefollowing speciiic examples but is not limited to the exact detailstherein set forth although in its more SPGClfiC aspects the morespecific features of the examples are included.

7 Ewample 1 parts of comminuted pumice are thoroughly precipitatedferric vanadate, 5 parts of potassium sulfate, 2 parts of potassiumchlorate, 2 parts of lithium carbonate and one part of potassium cyanidedissolved or suspended in 80 parts of water. The ferric vanadate mayadvantageously contain 10 percent excess of ferric oxide. The mass isformed into granules, dried and calcined at a temperature of 400 (1, andforms a catalyst which can be eflectivelyused for the catalyticoxidation of anthracene to anthraquinone and acenaph-' thene tonaphthalic anhyd'ride when the vapors of either hydrocarbon mixed with agreat excess of air are passed over the contact mass at 330400C.

After the-catalyst has become spent from use it can be readilyreactivated by means of oxides of nitrogen or by spraying with dilutenitric acid.

Example .2

i parts of kieselguhrv are mixed with a solution containing 12 parts. ofpotassium vanado-molybdate n 60 parts of water and.

colloidal silicic acid and 60' mixed with a suspension containing 6parts of ferric pyrovanad'ate in suspension. 8 parts of KOH in 25 partsof water are then added and the mass produced is formed into granules,dried, calcined at 400? (1., and then subjected to a subsequenttreatment of burner gases at d00-500 Q, until all the alkali istransformed into the sulfate or bisulfate.

. The contact mass is thenblown with air until acid gases no longerescape, and is then suited to a contact mass for the catalytic oxidationof anthracene to anthraquinone underthe reaction conditions described inthe foregoing example.

E ramp-Z6 3 280 partsof pumice meal or comminuted asbestos fibers aretreated with 2 percent of its weight of manganese sulfate containing '2mols of water which is introduced in the form of a 10% aqueous solution.A 10% solution of caustic alkali is then added, precipitating themanganese oxide in a finely divided condition; The'impregnated pumice isthen stirred into a 33 Be. waterglass solution containing about 24 to 30parts of SiO the solution having been previously diluted with about 5 to6 volumes of water. 9 parts of V 0 are dissolved in a normal sodiumhydroxide solution to form a sodium vanadate solution containingsufficient sodium hydroxide to cause the solution to react stronglyalkaline to litmus. To this solution 16 parts of Fe O in the form of a10 percent ferric sulfatev solution are addedto precipitate ferricvanadate mixed with ferric oxide.

18 parts of V 0 are mixed with 2 percent of their weight of concentratedsulfuric acid andthen diluted with 20 parts by weight of water. Thesuspension is boiled quietly and S0 containing gases are passed in untila clear blue solution of 'vanadyl sulfate is formed. The blue solutionis then gradually treated with lON sodium hydroxide solution, whichfirst precipitates out vanadyl hydroxide and then dissolves up theprecipitate to form a; clear coffee-brown solution of sodium vanadite.The waterglass suspension and the ferric vanadate-ferric oxide MnOsuspensions are poured together and the vanadite solution added withvigorous agitation. The major part of the excess alkali is neutralizedwith 10 percent sulfuric acid or 5 per cent nitric acid, or a mixture ofboth, and the gelatinous prod uct formed is pressed, washed two or threetimes with 200 parts of water and dried'at temperatures below 100 C. Theproduct is a. zeolite-like sodium-vanadyl polysilicate diluted withpumice'm-eal or asbestos fibres and'containing ferric vanadate, ferricoxide and manganese oxide in a fine state of subdivision. The stabilizerin this product is present in the form of a complex compound.

One mol of ammonium vanadate suspended in 300 parts-of water is treatedwith sulfur dioxide at an elevated temperature, producing a solution ofthe greenish bluevanadyl salt. The excess SO is then removed by boiling.One mol of a percent solution of copper sulfate is dissolved up insufficient '25 percent ammonia to form a deep blue cuprammonium sulfatesolution. 10 mols of SiO in the form of an ammoniacal 33 Be. potassiumor sodium waterglass solution are diluted with 10 volumes of water andsufficient cellite or pumice meal is stirred in to produ'ce'a suspensionwhich is just stirrable.

The vanadyl sulfate and cuprammonium sulfate solutions are then pouredinto the waterglass suspension heated up to about 65. O. In order toaccelerate the precipitation of the gel, dilute sulfuric acid may beadded cautiously until the mixture is weakly alkaline tophenolphthalein. After pressing in the usual manner the sodium ammoniumvanadyl copper zeolite produced can be treated with acids and issuitable for the catalytic oxidation of anthracene to anthraquinone.

Example 5 An iron zeolite is prepared by fusing 15.9

or three times with 200 parts of water, which produces hydration, isthen sprayed with a solution containing 6 to 8 parts of am--moniumvanadate dissolved in hot water. After calcining and subsequenttreatment --with acid such as dilute sulfuric or n1tr1c acid, thiscontact mass is well suited for the catalytic oxidation of anthracene toanthraquihone when anthracene vapors mixed with air in'theproportion ofair of 1 to are passed over thecontact mass at 340-380 C.

Example 6 36 parts of V 95 are suspended in 900 parts ofwater, 183.6parts of 100% KOH are added and the mixture warmed to 70 C. withvigorous agitatiomwhlch is continued until the "solution is complete.290 parts of celite or glaucosil .are stirredin and the product madeneutral to litmus with 2 mols of sulwfuric acid. Thereupon a solutioncontaming 52.8 parts of ferric sulfate in 800 parts of water is added.The reaction product obtained is sucked, Washed with about 1500 parts ofwater, dried and then pulverized. 88.8 parts of aluminum sulfate with 18mols of water are dissolved in, 600 parts of water and 450 volume partsof 2N potassium hydroxide solution is added with vigorous agitation,precipitating out aluminum hydroxide, which is filtered and-then washedwith about 800 parts of water. The wet aluminum hydroxide is thendissolved up'in a solution containing about 50.? parts of 100% KUH in 60parts of water. The diluted iron vanadate ismixed with potassiumaluminate solution and 125 parts of 38 B. po-

tassium waterglass is added, forming a moist mass which is easily formedinto fragments. The fragments are then dried'cautiously at about C. ina, stream of carbon dioxide and air producing an aluminum zeolite in'which the catalytically' effective material is embedded in the form ofa diluent.

I The contact mass is calcined at 400? C. and is then placedin. aconverter; 25-35% crude anthracene is vaporizedand thevapors mixed withair in the proportion of 1 to 20 by weight are passed over thecatalystat 330-350? C. The resulting reaction product contains 7 585% ofanthracene together with unimportant amounts of anthraquinone,

traces of-car'bazole and small amounts of used directly for thecatalytic oxidation of anthracene to anthraquinone or by a singlerecrystallization from solvent naphtha can be transformed into 90-95%anthracene, which can be used for catalytic oxidation or for the chromicacid oridation of anthracene to anthraquinone.

In the composite contact mass. described, the stabilizer and stabilizerpromoter form parts of the zeolite, the'alkali acting as a stabilizerand the aluminum oxide acting as stabilizer promoter.

Instead of iron vanadate, other vanadates can be used singly or inmixture, for example,

manganese, silver or copper vanadates. The

aluminum zeolite may be replaced with other zeolite compositions whichcombine stabilizers and stabilizer promoters. 7

If this catalytic composition is given a preliminary treatment withacids, e. g. diluted H 80 in orderto form the salt-like body of thezeolite, 25to 35% crude anthracene in the vapor phase mixed with air inthe ratio 1:20 by weight at 3'50 to 370 'C. can easily be converted tocrude anthraquinone containing 70 to 78% anthraquinone. The yield isvery good. a V

This application is a division v of my application Serial No. 196,393,filed June 3, 1927, which matured into Patent 583 dated April 23, 1929.

- ment falling within the group consisting WVhat is claimed as newis:'7 1. A method of oxidizing anthracene containing materials toanthraquinone, which comprises causing the anthracene containingmaterials in the vapor phase to react with an oxidizing gas at reactiontemperatures in the presence of a contact mass having associatedtherewith at least one compound of an eleof alkali metals, alkalineearth metals.

2. A method of oxidizing anthracene containing materials toanthraquinone, which comprises causing the anthracene containinginaterials'in the vapor phase to react with an oxidizing gas at reactiontemperatures in the presence of a contact mass having associatedtherewith at least one compound of an element falling within the groupconsisting of alkali metals, alkaline earth metals and at least onesolid catalyst included in the groupconsisting of hydrogenationcatalysts, dehydrogenation catalysts, reduction catalysts, oxidationcatalysts which, when used alone, are not specificcatalysts for theoxidation of anthracene to anthraquinone.

3. Amethod of oxidizing anthracene containing materials toanthraquinone, which comprises causing the anthracene containing materals in the vapor phase to react with an oxidizing gas at reactiontemperatures in the presence of a contact mass containlng a compound ofan element falling within the group consisting of alkali metals,alkaline earth metals and also containing an oxygen compound of vanadiumas at least one of its catalytically efiective components.

4. A method of oxidizing anthracene containing materials toanthraquinone, which comprises causing the anthracene containingmaterials in the vapor phase to react with an oxidizing gas at reactiontemperatures in the presence of a contact mass containing a compound ofan element falling'within the group consisting of alkali metalsalkaline. earth metals and also containing a vanadate as at least one ofits catalytically ponents.

5. A method of oxidizing anthracene containing. materials toanthraquinone, which comprises causing the anthracene containingmaterials in the vapor phase to react with an oxidizing gas at reactiontemperatures in the presence of a contact mass'containing a compound of:an element falling within the group consisting of alkali metals,alkaline earth metals and also containing an oxygen compound of ironvanadate as at least one of its catalytically effective components.

6. A methodof oxidizing impure anthracene to anthraquinone withconcomitant combustion of at least part of the impurities whichcomprises vaporizing the anthracene and passing the vapors admixed withan oxidizing gas at reaction temperatures over a contact masscontaining-at least one comefiective comassen phase catalytic oxidationof anthracene to anthraquinone, having associated therewith at least onepotassium compound. v

8. A method of oxidizing anthracene to anthraquinone, which comprisesvaporizing anthracene and causing the vapors to react with an oxidizinggas at-reaction temperatures in the presence ofa contact mass containingat least one zeolite which is the reaction product of at least onesilicate, at least one metallate and at least one salt, the basicradical of which is a metal capable of entering into thenon-exchangeable nucleus of a zeolite, the contact mass also containingat least one compound of an element falling within the group consistingof alkali metals,

alkaline earth metals.

9. A method of oxidizing anthracene to anthraquinone, which comprisesvaporizing anthracene and causing the. vapors to react with an oxidizinggas at reaction temperatures in the presence of a contact masscontaining at least one zeolite which is the reaction product of atleast-one silicate, at least one metallate and at least one salt, thebasic radical of which is a metal capable ofentering into thenon-exchangeable nucleus of a zeolite, the contact mass also containingat least one compound of an elementfallingwithin the group consisting ofalkali metals, alkaline earth metals, and at least one catalyst includedin the group consisting of hydrogenation catalysts, dehydrogenationcatalysts, reduction catalysts,-oxidation catalysts which, when usedalone, are not specific catalysts for the oxidation of anthracenetoanthraquinone.

10. A method of oxidizing anthracene to anthraquinone, which comprisesvaporizing anthracene and causing the vapors to react with an oxidizinggas at reaction temperatures in the presence of a contact masscontaining at least one zeolite which is the reactionproduct of at leastone silicate, at least one metallate and at leastone salt, the basicradical of which is a metal capable of entering into thenon-exchangeable nucleus of a zeolite, at least one compound of anelement falling within the group consisting of alkali metals, alkalineearth metals chemically combined in the zeolite. V

1-1. A method of oxidizing anthracene to anthraquinone, which comprisesvaporizing anthracene and causing the vapors to react with an oxidizinggas at reactiontemperatures in the presence of 'a contact masscontaining at least one zeolite which is the reaction product of atleast one silicate, at least one metallate and at least one salt, thebasic radical of which is a metal capable of entering into thenon-exchangeable nucleus of a zeolite, at least one compound of anelement falling within the group consisting of alkali metals, alkalineearth metals, and at least one catalyst included in the group consistingof hydrogenation catalysts, dehydrogenation catalysts, reductioncatalysts, oxidation catalysts which, when used alone, are not specificcatalysts for the oxidation of anthracene to anthraquinone, chemicallycombined in or with the Zeolite.

12. A method of oxidizing anthracene to anthraquinone, which comprisesvaporizing anthracene and causing the Vapors to react with an oxidizinggas at reaction tempera tures in the presence of a contact mass con- Ltaming at least one zeohte which is the reaction product of at least onesilicate, at least one metallate and at least one salt, the basicradical of which is a metal capable of entering into thenon-exchangeable nucleus of a zeolite, at least one compound of anelement falling Within the group consisting of alkali metals, alkalineearth metals, and at least one catalyst included in the group consistingof hydrogenation catalysts, dehydrogenation catalysts, reductioncatalysts, oxidation catalysts which, when used alone, are not specificcatalysts for the oxidation of anthracene to anthraquinone, chemicallycombined in or with the zeolite in non-exchangeable fprm.

13. A method according to claim 8, in which the associated compound is anon-alkaline compound of potassium.

14. A method according to claim 8, in

' which the associated compound is formed in situ by treating thecontact mass with acid gases.

Signed at Pittsburgh, Pa., this 21st day of March, 1928.

I ALPHONS O. JAEGER.

